IN space, nobody has seen an “Alien” movie: they have no idea what happens next. Down on Earth, however, we’re on the sixth: and it’s all too familiar. Directed — like its immediate prequel “Prometheus” and the original “Alien” — by Ridley Scott, “Covenant” raids its own trope cupboard, recycling plot points like the exhausted air in a ship that’s spent too long in deep space.

Shot entirely in Australia and New Zealand, and mostly on Fox soundstages, “Covenant” expends a great deal of its creative energies on star Michael Fassbender, playing dual roles. He’s David, the synth who featured in “Prometheus,” and also David’s “brother” Walter, a later-generation model on board the Covenant ship which is taking 2,000 pilgrims to settle in a new outpost on the far side of the galaxy a decade after the events of the last film.

“Covenant” starts with a prologue featuring David in conversation with his creator/father Peter Weyland (Guy Pearce). John Logan and Dante Harper’s script then moves quickly to Walter, who is manning the Covenant ship when a fire forces the occupants to abruptly emerge from their stasis. While “Prometheus” may have divided “Alien” fans, Fassbender’s eerily-blank, Lawrence of Arabia-loving android was easily equal to the memory left by Ian Holm as the original synth. Thus Scott has doubled up: we see emotional David, and now Walter, who has been engineered into submissiveness.

So fascinated is “Covenant” by the potential of Fassbender in a dual role, that this plot point overshadows the rest of the cast, or, at least, its human members. The Covenant’s captain (played by James Franco in a brief video flashback) is immediately immolated inside his hypersleep chamber, leaving his religious second-in-command Oram (Billy Crudup) to take over the ship with his widow, Daniels (Katherine Waterston) as first officer. The rest of the crew are placeholders, future hosts for the predatory Xenomorphs we know will soon make an appearance. There’s a nod to a gay couple, but it barely registers.

Visuals, thanks to DoP Dariusz Wolski, are low-key but insistent — neon tubes, sterile rooms, industrial corridors, a stock-issue flightdeck — when the crew starts to receive phantom messages from a nearby, hitherto-uncharted planet which appears to be habitable. “Alien” franchise veterans should feel the same unease as feisty Daniels when Oram decides to divert the ship there.

But Oram persists, docking a smaller exploration vessel on this beautiful, but uninhabited planet, which boasts a ruined structure which keen-eyed viewers may recognize. He’s even happy for his wife (Carmen Ejogo) to take a botanical side-trip, but as viewers aren’t particularly invested in her character — or any other crew member on the Covenant — it’s just a matter of waiting for the Xenomorphs to rip her apart, something that’s signaled by her cheery “I’m going to stop here – pick me up on your way back!”

The hope for something more substantial to feed on lies with David/Walter, as Covenant proceeds to lay waste to the team in increasingly squelchy, nasty ways - nobody survives a Xenomorph infestation, after all. The surprises here come mainly through the inventiveness of the movie’s superb creature-effects team.

Production values are not ostensibly lavish given the size of this film, or the scope of “Prometheus.” Soundstage work involving the pro forma Xenomorph pods has a pea-soupy air, while the ship interiors are surprisingly generic.